Class ReadTransformations

This command is invoked everytime the Qlist Filename entryfield is
invoked. If the Center Chooser checkbutton is on, the CenterChooser popup
dialog will come up to allow the center of rotation to be defined before
the transformation list is read in. If this is turned off, the center of
rotation defaults to either the previous center (if readTransformations
has been invoked previously for this molecule), or to the molecules
center of gravity. readTransformations then reads in lines from the file,
which have the format 'score tx ty tz rx ry rz theta rank'. These are
converted into a list of raw transformations (needed for writing out the
preferred list), and also a list of total transformations (which take
into account the center of rotation)